Purchasing and other transactions routinely occur over the Internet in electronic marketplaces. Electronic marketplaces typically allow buyers to locate suitable sellers and sellers to locate suitable buyers. However, establishing and maintaining an electronic marketplace is often expensive and time-consuming. For example, an electronic marketplace is typically built to order, which often requires a large initial investment by the owner of the marketplace. It is also often difficult to integrate the electronic marketplace into existing applications and systems, such as back-end legacy systems. In addition, it is often difficult to attract a sufficient number of customers to use the electronic marketplace.